Field of Disclosure
Wireless communications networks are widely deployed to provide various communication services such as voice, video, packet data, messaging, broadcast, and the like. These wireless networks may be multiple-access networks capable of supporting multiple users by sharing the available network resources.
Description of Related Art
A wireless communications network may include a number of access points. The access points of a cellular network may include a number of base stations, such as NodeBs (NBs) or evolved NodeBs (eNBs). The access points of a wireless local area network (WLAN) may include a number of WLAN access points, such as WiFi nodes. Each access point may support communication for a number of user equipments (UEs) and may often communicate with multiple UEs at the same time. Similarly, each UE may communicate with a number of access points, and may sometimes communicate with multiple access points or access points employing different access technologies. An access point may communicate with a UE via downlink and uplink. The downlink (or forward link) refers to the communications link from the access point to the UE, and the uplink (or reverse link) refers to the communications link from the UE to the access point.
As cellular networks become more congested, operators are beginning to look at ways to increase capacity, including the use of unlicensed spectrum to transmit cellular communications. In such approaches, timing and frequency synchronization among network devices associated with the same operator, as well as across different operators using the same unlicensed spectrum, may be useful. Traditional methods for network synchronization, however, may be challenging to implement in the context of unlicensed spectrum. For example, in a listen-before-talk (LBT) access scheme for unlicensed spectrum, a base station may be scheduled to transmit data during a time period that collides with the transmission of timing and frequency synchronization information by a neighboring device. Such collisions may prevent the base station from listening to the timing and frequency information from the neighboring device.